Need help backing up my music files

I'm trying to figure out the best way to back up my music files to DVD discs, so I have physical backups in case of a harddrive failure. I like to keep all my files organized on my harddrive, and keep them on there even after backing up to DVD so I can quickly swap out music to my mp3 player. So, here's the problem.
After I back up the files to a DVD, I want to make sure I know they've been backed up, so I won't have redundent files on DVDs. How can I do this while still keeping all of my files organized in the same folder?

My file setup is: my music/artist/album/track title.*

If the problem isn't clear, maybe an example will help. Say I back all of my files up onto a DVD, but then add a new album to an artist I already own. How can I make sure that the next time I backup my files, I only add this new album, and not the ones I've already backed up?